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Re: Association 'tween total duration of BF and Iron Deficie

Unless you subscribe to Pediatrics, all you can see is the abstract. Unless someone has access to the full text? I don't really want to comment just based on an abstract... Although I do note that the P value for the association between breastfeeding duration and lower serum ferritin was just P = 0.0015, which if I remember my biostatistics class correctly, is a very weak association. The usual value for determining statistical significance is generally set at P = 0.05.

Re: Association 'tween total duration of BF and Iron Deficie

Originally Posted by @llli*mommal

Although I do note that the P value for the association between breastfeeding duration and lower serum ferritin was just P = 0.0015, which if I remember my biostatistics class correctly, is a very weak association. The usual value for determining statistical significance is generally set at P = 0.05.

I think it is the opposite, actually--the smaller the P value, the less likely the result is due to chance. So P=0.0015 means there is only a 15/10,000 chance the result is just chance.

That said, it is still hard to draw conclusions without access to the full paper.

Re: Association 'tween total duration of BF and Iron Deficie

The study looked at the association between breastfeeding duration and serum ferritin, a marker of iron stores (lower ferritin suggests lower iron stores, though it is not a perfect measure). It did find a statistically significant association between longer duration of breastfeeding and lower serum ferritin, but not with iron deficiency anemia (ie, low hemoglobin/hematocrit as a result of low iron stores). Interestingly, the strongest association was with daily cow's milk intake - ie, more cow's milk intake, lower serum ferritin - drinking more cow's milk had a far bigger effect on ferritin than longer breastfeeding! For every additional month of breastfeeding, serum ferritin decreased by 0.24 micrograms/L, whereas drinking more cow's milk decreased ferritin by 1.85 micrograms/L (I believe this is for each additional cup of milk per day, it's not totally clear). And, they state, "Additional exploration identified an association between greater daily cow’s milk consumption and both shorter total breastfeeding duration and lower serum ferritin." They tried to deal with this statistically in their adjusted model, and found that prolonged breastfeeding still was associated with lower ferritin after adjustment, but as with any observational study, it is quite possible that there are other confounders that they didn't adjust for and that could be causing the association, rather than breastfeeding itself. Also, one thing to keep in mind is that they lumped all breastfeeding together, exclusive and non-exclusive, and they don't actually provide any information about the extent to which the breastfed infants were breastfed vs received other forms of nutrition.

All in all? Something to keep an eye on, certainly NOT a reason to curtail breastfeeding!

Re: Association 'tween total duration of BF and Iron Deficie

Re: Association 'tween total duration of BF and Iron Deficie

People who actually know what they are talking about, please rebut what I'm about to say, if necessary:

A baby who isn't bf is more likely to be given iron-fortified foods, like formula and those cutesy baby cereals. That type of iron isn't used as well in a human's body as the smaller amounts of iron naturally found in bm and, you know, real food.

So, couldn't the higher iron blood levels be because the iron is hanging around in the system, instead of getting used?

I'm always impressed (sarcasm) by studies that twist things around and make the bf group look special or different, when really bf groups should be your control group. They want you to think, "What us wrong with bf that it makes you have low iron?" Instead, You should say, "Hmmm...what is wrong with the non-bf group? Why do they have elevated iron levels?"